Ktor: Serializer for class 'JsonLiteral' is not found

Libraries
1

Recently updated my Ktor from 1.6 to 2.3.0 and some requests work fine but others have this error:

Serializer for class ‘JsonLiteral’ is not found.
Please ensure that class is marked as ‘@Serializable’ and that the serialization compiler plugin is applied.

It works fine when I switch back to 1.6 and nothing was changed in the data classes. I use kotlinx.serialization.

Ktor

import io.ktor.client.*
import io.ktor.client.call.*
import io.ktor.client.engine.cio.*
import io.ktor.client.plugins.contentnegotiation.*
import io.ktor.client.plugins.logging.*
import io.ktor.client.request.*
import io.ktor.client.statement.*
import io.ktor.serialization.kotlinx.json.*
import kotlinx.coroutines.*
import kotlinx.serialization.json.Json

    val httpClient: HttpClient = HttpClient(CIO) {
        expectSuccess = false
        install(ContentNegotiation) {
            json(Json {
                encodeDefaults = false
                ignoreUnknownKeys = true
                isLenient = true
                useAlternativeNames = false
            })
        }
        install(Logging) {...}
    }

build.gradle.kts

plugins {
    val kotlinVersion = "1.8.21"
    kotlin("jvm") version kotlinVersion
    kotlin("plugin.serialization") version kotlinVersion
//    id("org.jetbrains.kotlin.plugin.serialization") version kotlinVersion
    application
}

dependencies {
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:$kotlinVersion")
    implementation(kotlin("reflect"))
    testImplementation(kotlin("test"))

    // Ktor client
    implementation("io.ktor:ktor-client-core:$ktorVersion")
    implementation("io.ktor:ktor-client-cio:$ktorVersion")
    implementation("io.ktor:ktor-client-json:$ktorVersion")
//    implementation("io.ktor:ktor-client-serialization:$ktorVersion")
    implementation("io.ktor:ktor-serialization-kotlinx-json:$ktorVersion")
    implementation("io.ktor:ktor-client-content-negotiation:$ktorVersion")
    implementation("io.ktor:ktor-client-logging:$ktorVersion")

What is this JsonLiteral I’m hiddenly using? It’s marked as deprecated. Looks like some imports need to be upgraded or something inobvious.

2

It looks like something wrong with body in the POST requests (GETs are fine).

@Test
fun sendPost() = runBlocking{
    val requestData = "{\"search\":{\"dates\":\"current\"}}"
    val json = Json.parseToJsonElement(requestData)
    val result = Ktor.postAsync<HttpResponse>("http://127.0.0.1:8080", requestHeaders, json)
    assertEquals("", result.toString())
}

suspend inline fun <reified T> postAsync(url: String, headersMap: Map<String, String>, data: Any) = coroutineScope {
    return@coroutineScope httpClient.post(url) {
        for (element in headersMap) headers[element.key] = element.value
        setBody(data) // here?
    }.body<T>()
}

Please ensure that class is marked as ‘@Serializable’ and that the serialization compiler plugin is applied.

at app//kotlinx.serialization.internal.Platform_commonKt.serializerNotRegistered(Platform.common.kt:92)
at app//kotlinx.serialization.SerializersKt__SerializersKt.serializer(Serializers.kt:207)
at app//kotlinx.serialization.SerializersKt.serializer(Unknown Source)
at app//io.ktor.serialization.kotlinx.SerializerLookupKt.guessSerializer(SerializerLookup.kt:50)

With Ktor 2.0.0 this error is:

No request transformation found: {“search”:{“dates”:“current”}}

3

According to manual, now it’s needed to send a whole data class instead of its JSON. You need also to specify contentType.

val response: HttpResponse = client.post("http://localhost:8080/customer") {
    contentType(ContentType.Application.Json)
    setBody(Customer(3, "Jet", "Brains"))
}

There is a problem with settings appeared: encodeDefaults = false. Hope all my previous issues with Serialization fixed as for now and I can enable it.